Senior biologist Hector Moral holds two newly hatched Gentoo penguin chicks as he takes them back to their mother after weighing them at Moody Gardens Wednesday, Nov. 28, 2012, in Galveston. The chicks were born over the Thanksgiving holiday.

Photo: Brett Coomer, Houston Chronicle

Senior biologist Hector Moral holds two newly hatched Gentoo...

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Senior biologist Hector Moral weighs one of the two newly hatched Gentoo penguin chicks as biologist Sasha Francis looks on at Moody Gardens Wednesday, Nov. 28, 2012, in Galveston. The chicks were born over the Thanksgiving holiday.

Photo: Brett Coomer, Houston Chronicle

Senior biologist Hector Moral weighs one of the two newly hatched...

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One of the two newly hatched Gentoo penguin chicks is weighed at Moody Gardens Wednesday, Nov. 28, 2012, in Galveston. The chicks were born over the Thanksgiving holiday.

Photo: Brett Coomer, Houston Chronicle

One of the two newly hatched Gentoo penguin chicks is weighed at...

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A pair of Gentoo penguin chicks are weighed and examined at Moody Gardens Wednesday, Nov. 28, 2012, in Galveston. The chicks were born over the Thanksgiving holiday.

Photo: Brett Coomer, Houston Chronicle

A pair of Gentoo penguin chicks are weighed and examined at Moody...

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A pair of Gentoo penguin chicks are weighed and examined at Moody Gardens Wednesday, Nov. 28, 2012, in Galveston. The chicks were born over the Thanksgiving holiday.

Photo: Brett Coomer, Houston Chronicle

A pair of Gentoo penguin chicks are weighed and examined at Moody...

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Jerri Hamacheck, marketing and public relations manager at Moody Gardens, left, takes a photo of the two newly-hatched Gentoo penguin chicks Wednesday, Nov. 28, 2012, in Galveston. The chicks were born over the Thanksgiving holiday.

Photo: Brett Coomer, Houston Chronicle

Jerri Hamacheck, marketing and public relations manager at Moody...

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Biologist Sasha Francis stands by a pair of newly-hatched Gentoo penguin chicks at Moody Gardens Wednesday, Nov. 28, 2012, in Galveston. The chicks were born over the Thanksgiving holiday.

Photo: Brett Coomer, Houston Chronicle

Biologist Sasha Francis stands by a pair of newly-hatched Gentoo...

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The first of two Gentoo penguins "just popped out" on Thanksgiving, a Moody Gardens source said.

Photo: Brett Coomer, Houston Chronicle

The first of two Gentoo penguins "just popped out" on Thanksgiving,...

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Hector Moral weighs one of the two newly hatched Gentoo penguin chicks Wednesday at Moody Gardens as fellow biologist Sasha Francis provides an audience. The chicks were born over the Thanksgiving holiday.

Photo: Brett Coomer, Houston Chronicle

Hector Moral weighs one of the two newly hatched Gentoo penguin...

Image 10 of 12

Hector Moral weighs one of the two newly hatched Gentoo penguin chicks Wednesday at Moody Gardens as fellow biologist Sasha Francis provides an audience. The chicks were born over the Thanksgiving holiday.

Photo: Brett Coomer, Houston Chronicle

Hector Moral weighs one of the two newly hatched Gentoo penguin...

Image 11 of 12

Hector Moral weighs one of the two newly hatched Gentoo penguin chicks Wednesday at Moody Gardens as fellow biologist Sasha Francis provides an audience. The chicks were born over the Thanksgiving holiday.

The chicks were born Thanksgiving weekend at Moody Gardens, weighing in at a minuscule 23.4 and 11.8 grams, respectively.

Their arrival marks the eighth year of successful breeding of the aquarium's gentoo population. Gentoos, native to Antarctica, are known for their white-feather caps and colorful feet and beaks.

"We first discovered these guys in mid-October, and we were sort of keeping an eye out for them to hatch," Moody Gardens spokeswoman Stephanie Chan said. "As our biologists were cleaning and changing out the light bulbs and doing their daily routines on Thanksgiving Day, they noticed a chick when one of the parents stood up. The little guy just popped out."

More Information

About Gentoo penguins

Type: bird

Diet: carnivore

Average life span in the wild: 15 to 20 years

Size: 30 inches

Weight: 12 pounds

Fast fact: An adult gentoo penguin makes as many as 450 dives a day foraging for food.

SOURCE: National Geographic

Two days later, a smaller sibling hatched and burrowed into the warmth of its parents' protection. The chicks currently weigh 344 and 165 grams.

'Christmas tradition'

Facilities with penguins in captivity have generally good breeding results. During this year's mating season, staff members witnessed and captured the species' various mating rituals on video, including bowing and the collecting of stones for nests. Gentoos are easy to spot in the penguin exhibit because of their distinctive yellow feet.

"It's kind of a Christmas tradition here. We have chicks around Christmastime each year, and we fully expect these chicks are going to do very well," said assistant curator Diane Olsen. "They're going to grow up to be adults here in the next few months, and they'll join the colony with all the other birds."

The chicks are expected to be fully grown in eight weeks. Identifying the gender of gentoo penguins is extremely difficult because of their identical features. Feather samples will be used to test DNA to confirm their genders.

Because Moody Gardens is accredited by the Association of Zoos and Aquariums, the pair could be sent to other facilities throughout the country to promote breeding. But for now, they're best left to the care of their parents.

"The chicks are on exhibit for guests to see, and if they come and look in the center, they can see the chicks," Olsen said. "You might see the parents feeding them, so we encourage everyone to come to Moody Gardens and take a look."